The efficiency issue of turning over with Revit is a pressing problem to be solved. By analyzing the construction plans of the metro station structure, a method of automatically identifying the diaphragm wall is pro- posed, and, based on this method, this paper puts forward a method for distinguishing the shape of the ground connecting wall from the inside and outside sides. The C# programming language was used for secondary devel- opment based on the function database provided by Revit. According to the structure feature that the wall was closed in segments, an algorithm for rapidly identifying the continuous closed figures was developed. The drawing entities were drawn by using the closed polygons to complete the three -dimensional model. Through a large number of drawings’ validation, this method can accurately identify all the underground continuous walls in the drawings and generate 3D models to improve the modeling speed and efficiency.